(This contains Manga/Anime Spoilers)
I know this was way back in the Alabasta Arc, but has this ever been theorized or discussed? Ace, before he left the straw hat crew gave Luffy a wierd piece of paper, and said that if Luffy ever needed him, he would know what to do with the paper. After witnessing Ace's fight with Black Beard, I was thinking this piece of paper would be mentioned, but never again. One of One Piece's Mysteries that we have to wait for Hundreds of chapters to remember that small event and for it to be mentioned again. Was this unimportant, or just a joke? I remember Luffy put the paper under his hat, but after all the events and chaos of Alabasta, did this paper get lost/forgotten? Or does Oda have a future intention for this?
If this topic was already discussed sorry :(